This returns the text that this token holds. For example, parsing
C<foo> will return a C start-token, a text-token, and a C end-token. And
if you want to get the "foo" out of the text-token, call $token->text

$token->text(somestring)

This changes the string that this token holds. You probably won't need
to do this.

$token->text_r()

This returns a scalar reference to the string that this token holds.
This can be useful if you don't want to memory-copy the potentially
large text value (well, as large as a paragraph or a verbatim block)
as calling $token->text would do.